Hi everyone,
I’ve never flown this aircraft so I’m asking the correct procedure for takeoff regarding the throttle. I just set full throttle? Are there any climb or other detents (like the airbus just to be clear…) to set after takeoff?
Thanks in advance and sorry for my bad english…
First, I’ll recommend you get this mod because it is so much closer to the real thing:
Now, here is the real life procedure, or some of it, and I’m putting it here so it helps you understand what you’re doing in the sim and why you do it.
IRL, you would set your initial climb speed based on the flight plan (do you have an immediate sharp turn after takeoff, etc.?)
After dealing with the flight plan entry, push the TOGA button, and this will set your flight director to takeoff pitch.
Arm the autothrottle while taxiing and when you get on the runway, advance the throttle to about 50% and the autothrottle will take over the thrust levers from you and advance it fully to takeoff position.
During approach, leave autothrottle on and as soon as you cross the threshold, it will retard to idle by itself and autothrottle will disengage.
Now in the sim, the AT engages as soon as you arm it, so until it’s fixed, the recommended procedure is to not arm it. Set everything the way you should (set your speed to “selected” speed, not “managed” because VNAV doesn’t work yet).
Good initial speed would be the Vfto of 185 if you’re gonna be making a turn. If not, or the turn is mild then you can go all the way to 230 or even 250 depending on speed restrictions on your departure chart.
Default takeoff flaps is flaps 2. V Speeds are on the checklist in the forum.
Move your throttle to around 50% and then push the AT arm button (should have that bound to a button on your joystick or HOTAS throttle). Also when landing, disengage autothrottle just before you cross the threshold, and when you hear the “50” callout, retard your throttle to idle.
Example climb profiles:
250/270/78 = 250 until 10,000, then 270 until you reach mach 0.78, then switch to mach and maintain 0.78 until cruising altitude, then increase to mach 0.84 or as close to it as you can without getting an overspeed warning. For lowest fuel burn, stay between 41,000 and 45,000.
250/290/80 = 250 to 10,000; 290 to mach 0.80 and maintain mach 0.80 until cruising altitude, then increase to mach 0.84 or as close to it as you can manage without getting overspeed warnings.
You can fly either max speed or lowest fuel flow.
Max speed for most jets is at rather low altitudes, where the changeover from kts to Mach occurs, usually ~FL280.
With the Longitude, the higher you go the faster it goes, the lower the fuel burn. You could never achieve Mach 0.84 at 28,000.
That’s rather unusual. Thrust limited?
The engines on business jets or corporate jets like that are designed to fly as high as possible and as fast as possible. They’re optimized for these high altitudes. Not the same with the airliners, for instance, where the focus is on fuel economy vs speed. On bizjets, you higher to go faster. That’s why you fly at 41,000 - 45,000 even if you’re flying for just one hour.
That’s not the point. The question is why you can’t reach Mmo at low altitudes with the Longitude.
Did you get that from official Longitude performance tables?
The Longitude must be rather unique.
Looking at the Phenom 300 or CJ2+ performance tables, it’s the same as with most other jets,
the highest cruising speed occurs at the changeover altitude.
On the Longitude, with 4 passengers and a TOW of, say, 34,000 lbs, climbing @ 270 or 290, you intercept Mach 0.80 way after 30,000. In fact FL300+ is the changeover to Mach IIRC.
I’ll try it once more.
Can you confirm that the Longitude is unable to cruise at Vmo/Mmo at FL280 or 300?
The plane I primarily fly IRL gains about 15 kts TAS if we descend from FL430 down to FL310 (and the resulting fuel flow increases about 800 lbs per hr). It is very similar to the Longitude in performance, thrust, and operating weights, but has a different wing design. So I was curious how the Longitude compares.
Looks like the Longitude book numbers are identical. Same 15kt increase in speed if descending down to FL300, compared to FL430. Longitude changeover is at 29,375, vs ours at 29,475. Achieving Vmo/Mmo is never a problem at any altitude, except in vary rare circumstances (max weight / temps above average at FL450, etc).
That’s what I did assume…
Maybe you can edit your posts accordingly.
Yeah. I will.
Thanks guys! So, the engines can operate at full power until reaching the cruise altitude? Because if, after take off, i select FlightChange mode or a high Vertical Speed mode, the throttle is set to full power… I mean, there isn’t a CLB thrust setting, right?
No CLB setting because it has autothrottles.
All you need to do is set initial takeoff speed, say, 200, and during your takeoff roll, move your throttle to around 50% and arm the autothrottle (best if you bind it to a button). Once you do that, the thrust levers (throttles) will move forward by themselves to whatever position they need in order to achieve the 200 knots you set. Once you’re airborne, set your speed to 250 and the throttles will also move themselves to a new position to achieve that speed. Make sure your speed selector is on manual (I think it says “selected”). After you cross 10,000 feet, set your speed to either 270 or 290, and the thrust levers will again move forward in order to achieve that speed.
The thrust levers move back and forth by themselves when the autothrottle is armed.
Also, when descending, all you need is to set the speed you want, say mach 0.8 until your IAS reaches 290, then switch from mach to knots and maintain 290 until 10,000 feet, but reduce to 250 before you reach 10,000 so by 10,000 you’d already be at 250. You’ll notice that the throttles will keep backing off by themselves as you reduce speed.
Leave the autothrottle armed until just before you reach the threshold, but back off your physical throttles, but not all the way to idle. Place them on a position that is a bit lower than where they are in the sim. You can do this at the beginning of your descent so you don’t forget. Won’t affect your speed since you’re on Autothrottle.
Disengage the autothrottle just before you cross the threshold, but don’t touch the physical throttle.
As you reach 50 feet or cross the threshold (whichever comes first), back off your physical throttle all the way to idle. In real life, this would be done for you by the aircraft, but since it’s broken in the sim, you have to do it yourself.
This doesn’t anwser @UnveiledSpace24 question and that’s not the way the autothrottles work during climb (and descent).
Whatever speed you set, e.g. 250kts, the climb rates is variable, which means the engines are operating at e.g. max climb thrust and the throttles don’t move.
The question is, how and when does the Longitudes autothrottle system reduce thrust from takeoff to climb thrust?
I’m not familiar specifically with the Longitude but every jet I know of and / or have flown has a CAS / TAS / MACH envelope similar to this (Embraer 190/195 snail pace in the example below 
):
In other words, from change-over altitude upwards TAS will decrease until reaching the tropopause (TAS is represented by straight lines in the above graph).
